// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_DELEGATE_H_
#define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_DELEGATE_H_

#include <stdint.h>

#include "base/callback.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "content/common/content_export.h"
#include "content/public/browser/download_danger_type.h"
#include "content/public/browser/download_item.h"
#include "content/public/browser/download_url_parameters.h"

namespace content {
class DownloadItemImpl;
class BrowserContext;

// Delegate for operations that a DownloadItemImpl can't do for itself.
// The base implementation of this class does nothing (returning false
// on predicates) so interfaces not of interest to a derived class may
// be left unimplemented.
class CONTENT_EXPORT DownloadItemImplDelegate {
public:
    typedef base::Callback<void(
        const base::FilePath&, // Target path
        DownloadItem::TargetDisposition, // overwrite/uniquify target
        DownloadDangerType,
        const base::FilePath& // Intermediate file path
        )>
        DownloadTargetCallback;

    // The boolean argument indicates whether or not the download was
    // actually opened.
    typedef base::Callback<void(bool)> ShouldOpenDownloadCallback;

    DownloadItemImplDelegate();
    virtual ~DownloadItemImplDelegate();

    // Used for catching use-after-free errors.
    void Attach();
    void Detach();

    // Request determination of the download target from the delegate.
    virtual void DetermineDownloadTarget(
        DownloadItemImpl* download, const DownloadTargetCallback& callback);

    // Allows the delegate to delay completion of the download.  This function
    // will either return true (if the download may complete now) or will return
    // false and call the provided callback at some future point.  This function
    // may be called repeatedly.
    virtual bool ShouldCompleteDownload(
        DownloadItemImpl* download,
        const base::Closure& complete_callback);

    // Allows the delegate to override the opening of a download. If it returns
    // true then it's reponsible for opening the item.
    virtual bool ShouldOpenDownload(
        DownloadItemImpl* download, const ShouldOpenDownloadCallback& callback);

    // Tests if a file type should be opened automatically.
    virtual bool ShouldOpenFileBasedOnExtension(const base::FilePath& path);

    // Checks whether a downloaded file still exists and updates the
    // file's state if the file is already removed.
    // The check may or may not result in a later asynchronous call
    // to OnDownloadedFileRemoved().
    virtual void CheckForFileRemoval(DownloadItemImpl* download_item);

    // Return a GUID string used for identifying the application to the system AV
    // function for scanning downloaded files. If no GUID is provided or if the
    // provided GUID is invalid, then the appropriate quarantining will be
    // performed manually without passing the download to the system AV function.
    //
    // This GUID is only used on Windows.
    virtual std::string GetApplicationClientIdForFileScanning() const;

    // Called when an interrupted download is resumed.
    virtual void ResumeInterruptedDownload(
        std::unique_ptr<content::DownloadUrlParameters> params,
        uint32_t id);

    // For contextual issues like language and prefs.
    virtual BrowserContext* GetBrowserContext() const;

    // Update the persistent store with our information.
    virtual void UpdatePersistence(DownloadItemImpl* download);

    // Opens the file associated with this download.
    virtual void OpenDownload(DownloadItemImpl* download);

    // Shows the download via the OS shell.
    virtual void ShowDownloadInShell(DownloadItemImpl* download);

    // Handle any delegate portions of a state change operation on the
    // DownloadItem.
    virtual void DownloadRemoved(DownloadItemImpl* download);

    // Assert consistent state for delgate object at various transitions.
    virtual void AssertStateConsistent(DownloadItemImpl* download) const;

private:
    // For "Outlives attached DownloadItemImpl" invariant assertion.
    int count_;

    DISALLOW_COPY_AND_ASSIGN(DownloadItemImplDelegate);
};

} // namespace content

#endif // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_DELEGATE_H_
